The present invention relates to propulsion systems, and more particularly to an expander heat exchanger cycle system therefore.
A rocket engine provides propulsion by combusting propellants, such as fuel and an oxidizer, at high pressure. The combustion of the fuel and the oxidizers provide combustion gases which are expelled through a nozzle at high velocity to produce thrust.
A turbopump includes turbines which drive pumps that pump fuel and oxidizer to the combustion chamber of the rocket engine. High pressure gases power the turbines. In order to produce the high pressure gases, combustion devices such as pre-burners initially heat or combust certain propellants, which may be in a heat exchange relationship with the combustion chamber to transfer the high pressure gases therefrom to the turbomachinery. This, typically, requires the turbines to withstand high pressures and temperatures. In addition, a seal system is required to prevent pre-mixture of the propellants as pre-mixture may produce a system failure. The seal system is typically purged with a purge gas which is consumed in the seal system. The purge gas may be under relatively high pressure, which may further complicate the engine.
Accordingly, it is desirable to provide relatively low pressure and low temperature system to communicate power propellants to a rocket engine. 